This invention relates to a system for providing a continuous supply of web material to an applicator. This means a splicing system to add the leading end of a fresh roll of web material to the trailing end of an exhausted supply roll. The splicing system has to make a rapid and secure splice so the leading end of the new roll will be threaded into the applicator along a path created for the advance of the web material to the applicator without stopping the supply of web material to the machine. In one aspect the present invention provides an improved splicing system for hot melt adhesive tapes. The splicing system is adapted to make positive contact between the web material ends without special end structures, and the system uses sufficient tape tension sensing and braking mechanisms to avoid tensions that would break the tape or stop the tape while splicing the new roll to the expired supply roll.
The use of splices to join ends of rolls of web material is disclosed in a number of patents. One such patent is the U.S. Pat. No. 4,917,327, (Asbury, et al.), which discloses a splicing system for splicing the tail of one tape to the leading portion of another. The first tape 12 is provided at its trailing end with a pin element 16. A second tape 18 is provided at its leading end with a loop element 22. When the pin engages the loop, the tapes become linked, causing the trailing end of the first tape to pull the leading end of the second tape into the machine. The patent family includes U.S. Pat. No. 5,029,768 and Canadian Patent No. 1,280,097.
A splicing tape is known from U.S. Pat. No. 5,692,699, (Weirauch, et al.), disclosing a tape with a splicing portion (1,2) and an attachment portion (10″, 41). The tape disclosed has an attachment portion (10″, 41) for attaching the splicing portion (1,2) and separating the splicing portion from the surface of the underlying layer. This patent is directed to a specific splicing tape for use with a roll of paper to attach the end of the roll to the outer wrap on the roll.
A splicing method is disclosed in U.S. Pat. No. 5,913,991, (Kubota, et al.), for attaching a length of magnetic tape to a leader. The apparatus provides for aligning ends of the tapes with the ends of the leaders extending from a cassette and for splicing the ends using vacuum holders for the ends. There is no disclosure of splicing “on the fly”.
Another patent, U.S. Pat. No. 5,573,626, (Rossini et al.), discloses a tape splicing machine which can splice adhesive tapes in the supply roll to the lead end of the subsequent roll. The tapes 24 and 26 are guided to the splicing station and between the splicing rollers 212 and 252. When the supply tape nears the end and results in the triggering of the microswitch to actuate the solenoid 230, such that roller 212 is carried toward the roller 252 having the lead end of tape 44 positioned to contact the supply tape 42. When the splice is made, the tape 42 makes contact with the tape 44 and the splice is made and the tape 42 is cut. See columns 23 through 26. In column 24, beginning in line 56, the patent describes the manual set up necessary to make the next splice.
U.S. Pat. No. 5,624,526, (Perecman, et al.) is also directed to a tape splicing apparatus to splice a second tape to a supply tape in an apparatus to make the splice “on the fly.” The supply tape is directed through a guide in the splicing apparatus, where an applicator element is moved from a staging position toward the tape guide path to a splice position and then back to its staging position. The supply tape is then cut and the machine readied for the subsequent splice.